Among older American adults, men are two to three times more likely than women to receive an implantable cardioverter-defibrillator for prevention of sudden cardiac death, according to an article in the October 3 issue of the Journal of the American Medical Association.

The risk of sudden cardiac death increases with age and is higher in men than in women, although the sex difference narrows and eventually disappears after age 85 years, according to background information in the article.

Lesley H. Curtis, PhD, of Duke University School of Medicine, Durham, N.C., and colleagues examined the differences between men and women in the receipt of devices for the primary and secondary prevention of sudden cardiac death.

Data for the study came from a five percent national sample of files from the U.S. Centers for Medicare & Medicaid Services for the period 1991 through 2005. Patients in the primary prevention cohort were age 65 years or older and diagnosed with a myocardial infarction and either heart failure or cardiomyopathy. This group had 136,421 patients (65,917 men, 70,504 women). The secondary prevention cohort had a history of cardiac arrest or ventricular tachycardia. There were 99,663 patients (52,252 men, 47,411 women) in this group. All patients were treated from 1999 through 2005.

In the primary prevention group, 32.3 per 1,000 men and 8.6 per 1,000 women received a device within one year of entering the study. Men in were about 3.2 times more likely than women to receive a device. Among men and women alive at 180 days after group entry, the risk of death in the subsequent year was not significantly lower among those who received a device.

In the secondary prevention group, 102.2 per 1,000 men and 38.4 per 1,000 women received a device. After controlling for various factors, men were about 2.4 times more likely than women to receive a device. Among men and women alive at 30 days after entry, the risk of death in the subsequent year was 35 percent lower among patients who received a device.

“In this longitudinal analysis of Medicare beneficiaries at high risk for sudden cardiac death, we found significant sex differences in the use of ICD therapy from 1999 through 2005. Our findings in this cohort of elderly patients differ from an earlier study that suggested a narrowing of the gap between men and women, and they highlight the need for an improved understanding of sex differences in patterns of care,” the authors concluded.